So I started shopping around for a portable power solution for my HF radio. The battery I've been using does okay but the lack of pass through charging means I have a very finite amount of operating time and cannot sustain it with a solar panel while operating. Looking at the off the shelf solutions, everything was pretty underwhelming. The DC outputs just aren't enough on any of them. I was unable to find one that would do more than 10 amps. Even the fancy Goal Zero stuff came up short. My guess is that most (all?) of these companies are using a lithium cobalt battery that cannot sustain a high current draw. So I ended up building my own. I used a lithium iron phosphate battery that can handle much higher loads than the lithium cobalt. They are also a much more stable battery (they won't burst into flames like the videos you see on the internet of other lithium chemistries). They will also last for more charge cycles. The trade off is a lower power density than lithium cobalt. For my purposes, that isn't an issue. I used a 200 watt/hour lithium iron phosphate battery which fits perfectly inside this ammo box. The battery has a built in BMS so I didn't have to add one. It then powers 3 Anderson Powerpoles to run 12v devices (radio) and a pair of 2.4A USB connectors that will power my field computer. The fourth Powerpole is for charging. In the future I will be charging this in the field from a solar panel for essentially unlimited operating time. I also installed a power monitor that will measure my usage and let me know how much power I'm using. The switch is overkill: a 275A main battery disconnect switch that you'd see in a marine or RV application. But I wanted something relatively hard to activate so it wouldn't accidentally get switched on. The inside is a little messier than I would have liked. Hard working in there with big hands. But it's functional. I plan to get out into the field with it this weekend and see how it works.